Which option is a listed way HVAC creates IAQ problems?

• A. Improper venting of combustion products
• B. Refrigerant leakage
• C. Microbiological growth in drip pans
• D. All of the above

Answer: (D)

HVAC systems can affect indoor air quality through several pathways, especially when parts of the system are not functioning or maintained properly. Improper venting of combustion products allows toxic gases like carbon monoxide and other byproducts to accumulate indoors, which poses direct health risks to occupants. Refrigerant leakage introduces chemical contaminants into the air; even small leaks can irritate the eyes, throat, and lungs and can alter odor and comfort. Microbiological growth in drip pans happens when condensate sits stagnant and moist, creating a breeding ground for mold and bacteria that can release spores and VOCs into the circulating air. Taken together, each of these scenarios is a listed way HVAC can degrade IAQ, so “All of the above” is the best choice.